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Release status: experimental

Description Self-printable RepRap
License GPL
Author Rhombot
Based-on [[]]
Categories XYZ-head DriveTrains
CAD Models
External Link Thingiverse

Printed example of the Rhombot


The Rhombot is a printable XYZ stage based on 3 chains of rhombus shapes. It is currently just an early alpha version.

The Rhombot can be used with Makerbot motors, electronics, and extruders. All parts can be built in a Makerbot, or in itself. It has no rods, belts, pulleys, nuts, threads, screws (other than the screws on the motor), sarrus hinges, moving towers, or moving motors.

It is designed so the extruder and motors are stationary, and the green build platform moves in 3D beneath an extruder without rotating. Each dimension of motion is controlled by a separate motor, rather than having Z controlled by a combination of motors, and X controlled by a different combination of the same motors, etc. This may be helpful in keeping it stationary in the Z direction while it moves back and forth in X and Y. When this first version was printed and tested, the motion appeared to be smooth, with little backlash, and with a surprising amount of stability in the Z direction while moving in X and Y.

Further reading

  • See the description on Thingiverse at http://www.thingiverse.com/thing:5432
  • The rhombus linkages are vaguely similar to the Sarrus Z02 -- can we start from there as a rough draft, or must we start from scratch?
    • Probably from scratch. The constraints are different in the two cases, which leads to different designs.
  • There has been a brief discussion[1] of a similar parallel Cartesian drive train.[2].
    • That robot has some similarities, but it requires 3 sets of rails, so either all 3 motors move, or there are 3 belts. In the Rhombot, there are no rails, belts, or moving motors.
  • Eliminating rails is a big step towards a fully printable reprap
  • pinned hinges
stl_to_print Model Assembly These are stl files needed to print out the Rhombot .zip LDeSci 3:35 PM, 27 February 2011 (MST)